Combination Of Total Body Irradiation Research Articles

Updated Analysis on the Outcomes of Children with Acute Leukemia (AL) Receiving an Alpha/Beta T and B-Cell Depleted HLA-Haploidentical Hematopoietic Stem Cell Transplantation (TBdepl-haploHSCT)

Background: We previously reported (Locatelli et al., Blood 2017) that TBdepl-haploHSCT is a suitable and effective option for children with AL lacking an HLA-compatible donor and/or needing an urgent allograft. This type of transplant is characterized by a low incidence of both acute and chronic graft-versus-host disease (GvHD) and by low non-relapse mortality (NRM), translating into survival outcomes comparable to those of patients transplanted from an HLA-compatible donor. Here we report an update on a cohort of 213 children with AL of our study, with a minimum follow-up of 180 days after the allograft. Patients and methods: Between October 2010 and January 2022, 213 children with AL received TBdepl-haploHSCT from an HLA-partially matched relative at Ospedale Pediatrico Bambino Gesù in Rome, Italy. All patients were in morphological complete remission (CR) and were prepared to TBdepl-haploHSCT using a fully-myeloablative conditioning regimen including a combination of total body irradiation (TBI) and/or cytotoxic drugs. All patients received also anti-T-lymphocyte globulin (ATLG) before transplantation (12 mg/kg total dose, from days -5 to day -3) to modulate bi-directional donor/recipient alloreactivity and rituximab (200 mg/sqm) on day -1 to prevent post-transplantation EBV-induced lymphoproliferative disorders (PTLD). No patient received any post-transplant pharmacological GvHD prophylaxis. Data were analyzed as of July 15, 2022. Results: Table 1 reports details on characteristics of patients included in the analysis. The median follow-up of surviving patients is 47.6 months (range: 6 months - 11.7 years). Two hundred and eight patients (98% of the total number) engrafted with a median time to neutrophil and platelet recovery of 13 (range 9-24) and 11 (range 7-23) days, respectively. Only 5 patients experienced graft failure; all were rescued with a second allograft. Eleven out of the 213 patients (5%) died of transplant-related complications (4 because of idiopathic pneumonia, 2 each because of disseminated adenovirus infection and thrombotic microangiopathy and 1 each of cardiac insufficiency, combined CMV/rhinovirus pneumonia and sepsis from Pseudomonas aeruginosa), the 5-year cumulative incidence of NRM being 5.2% (95% CI, 2.8-8.8). Forty-four patients relapsed at a median time of 192 days (range 56-1711) after HSCT, the 5-year cumulative incidence of relapse being 22.7% (95% CI, 16.9-29.2). Cumulative incidence of grade II-III acute GvHD was 14.7% (95% CI 10.6-20.3). Three patients and 1 developed gut and liver GvHD, respectively, while for all other patients skin was the sole organ involved. Fourteen out of the 193 patients at risk developed chronic GvHD, in all cases of limited severity, the cumulative incidence of this complication being 8.1% (95% CI 4.8-13.3). The 10-year probability of overall and leukemia-free survival (LFS) were 75.4 (95% CI 68.6-80.9) and 71.6% (95% CI 64.4-77.6), respectively. In univariate analysis, disease status at transplantation (CR1 vs CR2 vs CR>3), use of TBI during the preparative regimen and age at transplant above the median value (9.5 years) were associated with better patient's outcome, mainly because of a reduced incidence of relapse. Notably, among TBI-based regimens, the use of thiotepa and fludarabine was associated with an improved DFS as compared to other combinations (82.4% vs 63.9%, p=0.01). In a multivariable model for LFS including also gender and type of disease, only TBI (hazard ratio (HR) 0.38 (95% CI, 0.17-0.85, p=0.01) and disease status at HSCT (HR 1.72 (95% CI, 1.05-2.79, p=0.02) remained statistically significant. The 10-year GvHD/relapse-free survival was 65.1% (95% CI 57.7-71.4). The median CD3+ cell count on day +30, +90, +180 and +360 were 140, 185, 533 and 1058 /mcl, respectively. Conclusions: TBdepl-haploHSCT is becoming a widespread haplo platform for pediatric patients affected by both malignant and non-malignant disorders. This cohort of homogeneously treated patients, the largest reported so far with a median follow-up of almost 4 years, confirm once more the effectiveness and safety of this approach. Furthermore, this analysis identified subgroups of patients (e.g., those in CR>3) for whom post-transplant strategies aimed at reducing the risk of relapse (the main cause of treatment failure) are desirable. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

The incidence of severe oral mucositis in patients undergoing different conditioning regimens in haematopoietic stem cell transplantation

PurposeOral mucositis is a common complication during haematopoietic stem cell transplantation (HSCT). This study aimed to assess the incidence of severe mucositis in patients undergoing different HSCT regimens.MethodsThis single-centre retrospective study reviewed daily oral assessment for 467 consecutive patients who underwent different transplant regimens for matched unrelated or related allogeneic HSCT with post-transplant methotrexate, haploidentical or mismatched HSCT with post-transplant cyclophosphamide (PTCy), or autologous HSCT. Oral care and cryotherapy with melphalan were used. Patient demographic data, oral mucositis WHO grade, use of total parenteral nutrition (TPN) and patient-controlled analgesia (PCA) were collected.ResultsGrade 3–4 oral mucositis was common in myeloablative total body irradiation (TBI)-based regimens cyclophosphamide/ TBI (CyTBI) (71%) and fludarabine/ TBI (FluTBI) with PTCy (46%), as well as reduced-intensity fludarabine/melphalan (FluMel) (43%) and carmustine/etoposide/cytarabine/melphalan (BEAM) autologous HSCT (41%). In contrast, grade 3–4 oral mucositis was less common in reduced-intensity haploidentical regimen melphalan/fludarabine/TBI with PTCy (19%), all non-myeloablative regimens (0–9%) and high-dose melphalan autologous HSCT (26%). TPN and PCA use were correlated to oral mucositis severity.ConclusionsSevere oral mucositis was associated with myeloablative TBI, methotrexate and melphalan in combination with methotrexate and in BEAM. Use of PTCy was preferable over methotrexate to prevent oral mucositis.

Long-Term Follow-Up of Multiple Myeloma Patients Treated with Tandem Autologous Transplantation Following Melphalan and Upon Recovery, Total Marrow Irradiation

Total body irradiation in combination with melphalan for multiple myeloma (MM) has been shown to be prohibitively toxic. To ameliorate toxicity, total marrow irradiation (TMI) has been administered as the sole ablative modality during the second cycle of tandem autologous stem cell transplantation (TASCT) for MM patients on a phase I-II trial. Patients with MM in response or with stable disease and ≤18 months from diagnosis received melphalan 200 mg/m2 and autologous stem cell transplantation (ASCT) (cycle 1) and then, after recovery, TMI and another ASCT (cycle 2), followed by maintenance with an immunomodulatory drug (ImiD) and dexamethasone for up to 12 months. TMI doses were escalated from 1000 cGy to 1800 cGy in 200-cGy increments. Fifty-four patients were to receive TASCT between 2004 and 2011; 8 patients received single ASCT because of patient or physician preference. The median time between melphalan and TMI was 65 days (range, 47 to 125 days). Thirty patients (55.6%) underwent TASCT at the maximum tolerated dose of 1600 cGy. The complete response and very good partial response rates were 48.1% and 22.2%, respectively, following ASCT and maintenance. The median follow-up among survivors was 12.3 years (range, 9.2 to 15.5+ years). Progression-free survival (PFS) and overall survival at 10 years were 20.4% (95% confidence interval [CI], 10.9% to 31.9%) and 38.8% (95% CI, 25.9% to 51.5%), respectively. Secondary neoplasms included (1 each) acute myelogenous leukemia, papillary thyroid and prostate carcinoma, and melanoma, and there was 1 case of ductal carcinoma in situ and 4 cases of nonmelanoma skin cancers. TMI as part of TASCT was well tolerated, and TASCT was associated with a 20.4% PFS plateau. The inclusion of TMI as a conditioning regiment for MM before ASCT warrants further study in the context of modern induction and maintenance therapies.

Optimized Conformal Total Body Irradiation Among Recipients of TCRαβ/CD19-Depleted Grafts in Pediatric Patients With Hematologic Malignancies: Single-Center Experience

Total body irradiation (TBI) in combination with chemotherapy is widely used as a conditioning regimen in pediatric and adult hematopoietic stem cell transplantation (HSCT). The combination of TBI with chemotherapy has demonstrated superior survival outcomes in patients with acute lymphoblastic and myeloid leukemia when compared with conditioning regimens based only on chemotherapy. The clinical application of intensity-modulated radiation therapy (IMRT)-based methods (volumetric modulated arc therapy (VMAT) and TomoTherapy) seems to be promising and has been actively used worldwide. The optimized conformal total body irradiation (OC-TBI) method described in this study provides selected dose reduction for organs at risk with respect to the most significant toxicity (lungs, kidneys, lenses). This study included 220 pediatric patients who received OC-TBI with subsequent chemotherapy and allogenic HSCT with TCRαβ/CD19 depletion. A group of 151 patients received OC-TBI using TomoTherapy, and 40 patients received OC-TBI using the Elekta Synergy™ linac with an Agility-MLC (Elekta, Crawley, UK) using volumetric modulated arc therapy (VMAT). Twenty-nine patients received OC-TBI with supplemental simultaneous boost to bone marrow—(SIB to BM) up to 15 Gy: 28 patients (pts)—TomoTherapy; one patient—VMAT. The follow-up duration ranged from 0.3 to 6.4 years (median follow-up, 2.8 years). Overall survival (OS) for all the patients was 63% (95% CI: 56–70), and event-free survival (EFS) was 58% (95% CI: 51–65). The cumulative incidence of transplant-related mortality (TRM) was 10.7% (95% CI: 2.2–16) for all patients. The incidence of early TRM (<100 days) was 5.0% (95% CI: 1.5–8.9), and that of late TRM (>100 days) was 5.7 (95% CI: 1.7–10.2). The main causes of death for all the patients were relapse and infection. The concept of OC-TBI using IMRT VMAT and helical treatment delivery on a TomoTherapy treatment unit provides maximum control of the dose distribution in extended targets with simultaneous dose reduction for organs at risk. This method demonstrated a low incidence of severe side effects after radiation therapy and predictable treatment effectiveness. Our initial experience demonstrates that OC-TBI appears to be a promising technique for the treatment of pediatric patients.

Tolerance and efficacy of total body irradiation and cladribine prior to allogeneic hematopoietic cells transplantation in patients with acute myeloid leukemia and myelodysplastic syndromes — synopsis of clinical study

Introduction: Allogeneic hematopoietic cell transplantation (allo-HCT) is a standard of care for patients with acute myeloid leukemia (AML) and patients with intermediate and high-risk myelodysplastic syndrome (MDS). Despite many years of experience. there is still no standard for conditioning regimen. The aim of this study is to analyse the efficacy and safety of a conditioning treatment with cladribine in combination with total body irradiation (TBI). Material and methods: A group of 40 adult patients referred for allo-HCT due to AML and MDS are to be enrolled in the study. The inclusion criteria are: informed consent, chemo-sensitivity for cladribine treatment regimens (when used in induction therapy), age 18–60, and performance status 0–2 according to World Health Organization. The conditioning regimen consists of cladribine and TBI at a total dose of 12 Gy in three fractions given over three consecutive days. The goal of the study is to assess the tolerability and efficacy of the regimen. Results: Our results may stimulate further investigation in this field i.e. phase III trials to compare this regimen to others. Conslusion: A myeloablative conditioning regimen consisting of total body irradiation in combination with cladribine may contribute to improved outcomes after allo-HCT for AML and MDS patients.

High Progression-Free Survival after Reduced Intensity Total Body Irradiation-Based Conditioning in Patients Allografted for Chronic Myelomonocytic Leukemia (CMML)

High Progression-Free Survival after Reduced Intensity Total Body Irradiation-Based Conditioning in Patients Allografted for Chronic Myelomonocytic Leukemia (CMML)

HGG-54. HISTOLOGICAL AND MOLECULAR CHARACTERIZATION OF HIGH-GRADE BRAIN TUMORS SECONDARY TO TOTAL BODY IRRADIATION FOR HEMATOLOGICAL MALIGNANCIES

INTRODUCTIONHematopoietic stem cell transplantation (HSCT) is increasingly used in the treatment of acute leukemias (AL), non-Hodgkin lymphomas and other primary malignancies. However, a growing number of neoplasms secondary to HSCT are reported. The combination of total body irradiation (TBI) and high dose chemotherapy (HD-CT) as conditioning regimen is considered a risk factor. We present four children who survived AL, treated with HSCT and conditioning regimens including TBI/HD-CT. These patients developed a high-grade-brain tumor. We analyzed histological and molecular characteristics of neoplasms.METHODSHistologically, tumors were assessed for: presence of mitosis, necrosis and vascular proliferation; expression of ki67; expression of neuronal and glial markers, p53 and therapeutic targets. We analyzed the DNA methylation profile (DMP) of all tumors using IlluminaEPICarrays and compared it to the brain tumor classifier which allowed to generate the CNVs.RESULTSMorphologically two cases were defined as anaplastic astrocytoma, two cases as glioblastoma. Based on the DMP, all cases were found to belong to the methylation class “glioblastoma, IDH wildtype, subclass midline”, hypermutants, with gain of chromosome 1q and loss of 1p. Two cases showed PDGFRA amplification. All patients were treated with Temozolomide combination therapy +/- Bevacizumab and radiation therapy. At progression three patients were treated with checkpoint inhibitors.CONCLUSIONSThe improvement of the precision medicine is fundamental in the therapeutic decision of brain tumors and even more in neoplasms secondary to antiblastic treatments. DMP and CNV have proven to be useful tools to complement the histological characterization of the reported cases.

Unusual Case of Hepatic Sinusoidal Obstruction Syndrome Induced By Low Dose Oral Cyclophosphamide

Hepatic sinusoidal obstruction syndrome (SOS) has been reported in patients receiving high dose intravenous (IV) cyclophosphamide especially as a part of preparative regimen for hematopoietic stem cell transplantation. Hepatic SOS from low dose oral cyclophosphamide has not been reported. Here we present a rare case of hepatic SOS induced by low dose oral cyclophosphamide. A 78-year-old male with history of coronary artery disease status post coronary artery bypass graft (CABG) was initially seen in hematology clinic for evaluation of normocytic anemia. During workup, bone marrow biopsy revealed NK cell large granular lymphocytic leukemia (LGL). He was then started on low dose oral cyclophosphamide 50 mg daily. After 2 months, his dose was reduced to 25 mg daily due to severe neutropenia. He then tolerated cyclophosphamide well and his hemoglobin (Hb) improved from his baseline 8 gm/dl to 12 gm/dl in 4 months. After 6 months of treatment, he was admitted to the hospital for abdominal distension, ascites and 15 pounds weight gain over 3 weeks. Labs most prominent on admission were Hb of 12.5 gm/dL , WBC 5.3 x 103/µL, Platelets 197 x 103/µL, total bilirubin 1.6 mg/dL, aspartate aminotransferase (AST) 89 U/L , alanine aminotransferase (ALT) 35 U/L and alkaline phosphatase (ALP) 283 U/L. Workup of ascites included abdominal paracentesis which revealed serum ascites albumin gradient(SAAG) &amp;lt;1.1 and fluid cytology was negative for carcinoma. Ultrasound of abdomen showed diffuse parenchymal heterogeneity and increased echogenicity of liver with patent hepatic vessels with normal direction of blood flow. Echocardiogram revealed preserved left ventricular systolic function with estimated left ventricular ejection fraction of 60%. He then underwent transjugular liver biopsy which revealed chronic lymphoproliferative disorder of NK cells, prominent centrilobular sinusoidal dilatation and congestion, lobular disarray, cholestasis and sinusoidal fibrosis suggestive of veno-occlusive disease secondary to drug/toxin induced liver injury. The Naranjo adverse drug reaction probability scale indicated a probable relationship between hepatic SOS and cyclophosphamide. Cyclophosphamide was held. Bone marrow biopsy showed the patient was in remission. His liver enzymes are improving and hematologic counts continue to be stable while on observation. High dose of IV cyclophosphamide given as myeloablative therapy in combination of total body irradiation or busulfan (or other agents) in preparation for hematopoietic stem cell transplantation can induce hepatic SOS, which can be severe leading to acute liver failure and death. The diagnosis is usually based on clinical features of tender hepatomegaly, weight gain, ascites and jaundice. Liver biopsy is usually diagnostic. Mechanism of injury is related to direct toxic effects of cyclophosphamide on sinusoidal cells in the liver, causing their necrosis and release into the sinusoids, obstruction and obliteration of hepatic veins. This case demonstrates that hepatic SOS can also be caused by low dose oral cyclophosphamide. Given this rare occurrence, it is prudent for the clinicians to keep an open mind and consider hepatic SOS as a potential side effect even with oral cyclophosphamide. Disclosures Yacoub: Novartis: Speakers Bureau; Agios: Honoraria, Speakers Bureau; Incyte: Speakers Bureau; Hylapharm: Current equity holder in private company; Cara Therapeutics: Current equity holder in publicly-traded company; Ardelyx: Current equity holder in publicly-traded company; Dynavax: Current equity holder in publicly-traded company; Roche: Other: Support of parent study and funding of editorial support.

Reduced Risk of Relapse for Total Body Irradiation + Fludarabine Compared to Busulphan + Fludarabine As “Reduced-Toxicity” Conditioning for Patients with Acute Myeloid Leukemia Treated with Allohsct in First Complete Remission. a Study By the Acute Leukemia Working Party of the EBMT

Background: Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a standard of care for patients with acute myeloid leukemia (AML) being at high risk of relapse. However, the procedure using conventional myeloablative conditioning regimens based on either busulphan (Bu) or total body irradiation (TBI) in combination with cyclophosphamide is associated with significant risk of non-relapse mortality (NRM). The use of reduced-intensity or non-myeloablative conditioning regimens results in improved tolerance but increased incidence of disease recurrence. In order to reduce toxicity while maintaining the efficacy, alternative approaches have been proposed including the use of moderately reduced doses of Bu or TBI in combination with fludarabine (Flu). The goal of this retrospective study to compare BuFlu and TBI/Flu reduced-toxicity regimens. Patients and methods: Adult patients with AML treated in CR1 with alloHSCT from either HLA-matched sibling or unrelated donor between January 2006 and June 2018 were included in the analysis. The following conditioning regimens have been selected for the comparison: intravenous Bu at a total dose 9.6 mg/kg (3 days) + Flu (Bu3Flu, N=350) or TBI at a total dose of 8 Gy + Flu (TBI8Flu, N=168). In both groups the proportion of patients with intermediate risk karyotype was 74% while high risk - 24%. The proportion of patients with secondary AML was also the same (14%). Patients in the Bu3Flu group were significantly older, were treated more frequently with alloHSCT from unrelated donors and were treated in more recent period. Results: The engraftment rate was 99% for both regimens. In a univariate analysis the use of TBI8Flu was associated with reduced incidence of relapse (20% vs. 30% at 2 years, p=0.01) and tendency to increased leukemia-free survival (LFS; 66% vs. 60%, p=0.15) and overall survival (OS; 74% vs. 58%, p=0.051) as well as reduced incidence of grade III-IV acute graft-versus-host disease (GVHD, 4% vs. 9%, p=0.03). The effects on non-relapse mortality (NRM), grade II-IV acute GVHD and chronic GVHD were not significant. In a multivariate analysis a chance of LFS was reduced for patients with high risk karyotype and secondary AML, with no effect of donor type. Due to significant interaction between type of conditioning and age, further analyses were performed stratifying patients above or below 50 years. For patients ≤50 y.o. the use of TBI8Gy was associated with reduced incidence of relapse (21% vs. 35%; Cox model: HR=0.49, p=0.049), tendency to improved NRM (4% vs. 7%,; HR=0.17; p=0.1), significantly improved LFS (75% vs. 58%, p=0.02; HR=0.45, p=0.02), improved OS (84% vs. 60%; HR=0.29, p=0.002) improved survival free from both GVHD and relapse (GRFS; 56% vs. 46%; HR=0.53, p=0.02) and reduced incidence of grade II-IV acute GVHD (15% vs. 26%; HR=0.53, p=0.02). For patients &amp;gt;50 y.o. the effect of TBI8Flu on relapse was not statistically significant (19% vs. 29%; HR=0.64, p=0.21) while this regimen was associated with increased risk of NRM (26% vs. 11%; HR=3.98, p=0.0006) leading to a tendency to decreased OS (59% vs. 63%; HR=1.53, p=0.1). Conclusion: Reduced-toxicity regimens using either TBI8Flu or Bu3Flu for patients with AML in CR1 are associated with relatively low risk of relapse and NRM leading to enhancing survival rates after alloHSCT. The use of TBI8Flu appears more effective compared to Bu3Flu and may be advised in younger patients where reduced risk of relapse translates into improved survival. In older individuals it should be used with caution due to increased risk of NRM. Prospective studies are needed to verify our findings. Disclosures Labopin: Jazz Pharmaceuticals: Honoraria. Byrne:Ariad/Incyte: Honoraria, Speakers Bureau. Beelen:Medac GmbH Wedel Germany: Consultancy, Honoraria. Blaise:Jazz Pharmaceuticals: Honoraria; Molmed: Consultancy, Honoraria; Sanofi: Honoraria; Pierre Fabre medicaments: Honoraria. Mohty:Jazz Pharmaceuticals: Honoraria, Research Funding.

CD45-Targeted Antibody Drug Conjugate Plus Post Transplant Cytoxan Is Sufficient to Enable Allogeneic Bone Marrow Transplant in a Minor Mismatch Mouse Model

Bone Marrow Transplant (BMT) is a potentially curative treatment for malignant and non-malignant blood disorders. Current regimens for patient preparation, or conditioning, prior to BMT limit the use of this curative procedure due to regimen-related mortality and morbidities, including risks of organ toxicity, infertility and secondary malignancies. Targeted preparation using antibody drug conjugates (ADCs) to mouse CD45 has previously been shown to be sufficient to enable bone marrow transplant (BMT) in syngeneic immune competent mice (Palchaudhuri et al. Nature Biotech 2016 34:738–745), and this approach to preparation has the potential to expand the utility of BMT if it can be successfully translated to patients. To further investigate the utility of this tool ADC in murine transplant models, we explored anti-CD45-saporin (CD45-SAP) in an allogeneic minor mismatch transplant model (Balb/c donor into DBA/2 recipients). The goal of the work was to identify the level of immune suppression, if any, that needs to be used in combination with CD45-SAP to enable high donor chimerism in the allogeneic setting. CD45-SAP (1.9 mg/kg, iv) was evaluated alone or in combination with additional immune modulating agents: clone 30F11 (25 mg/kg, IP), a naked anti-CD45 antibody that mimics ATG by relying on effector function to enable potent peripheral B- and T -cell depletion; pre-transplant Cytoxan (PreTCy, 200 mg/kg, IP), 2 Gy total body irradiation (TBI), and post-transplant Cytoxan (PTCy, 200 mg/kg, IP) to prevent graft versus host disease as well as block host versus graft rejection. 9 Gy TBI was used as the conventional conditioning positive control. Conditioned mice were transplanted with 2 × 107 whole bone marrow cells, and chimerism assessed over 12 weeks. CD45-SAP in combination with PTCy achieved comparable peripheral myeloid chimerism, a readout of stem cell engraftment, to 9 Gy TBI (>90%) at 8 weeks post-transplantation (Fig 1). The addition of 30F11 to the CD45-SAP/PTCy protocol had no effect on peripheral donor chimerism (59% vs 61%), suggesting additional lymphodepletion is not required. In contrast, the single agents alone, 2 Gy TBI in combination with 30F11 and PTCy resulted in These results indicate CD45-SAP in combination with PTCy is sufficient to enable high levels of donor chimerism in the minor mismatched setting without the need for additional immune suppression. CD45-SAP was more effective at conditioning than 2Gy TBI or PreTCy. Future experiments will investigate the CD45-SAP/PTCy protocol in haploidentical and fully mismatched allogeneic mouse models.

Comparison of Myeloablative Conditioning Regimes Based on Either Busulfan or Total Body Irradiation in Combination with Fludarabine for Patients with Acute Myeloid Leukemia. a Study on Behalf of the Polish Adult Leukemia Group

Background: Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a standard of care for patients with high risk acute myeloid leukemia (AML). However, the procedure using conventional myeloablative conditioning regimens based on either busulphan (Bu) or total body irradiation (TBI) in combination with cyclophosphamide is associated with significant risk of non-relapse mortality (NRM). The use of reduced-intensity conditioning regimens results in improved tolerance but increased incidence of disease recurrence. In order to reduce toxicity while maintaining the anti-leukemic efficacy alternative conditioning regimens have been proposed including the use of Bu or TBI in combination with fludarabine (Flu). The goal of this retrospective, multicenter study was thus to compare Bu4Flu and TBI12Gy/Flu.Patients and methods: Adult patients with AML treated with alloHSCT from either HLA-matched sibling (MSD) or unrelated donor (URD) between year 2012 and 2017 were included in the analysis. The following conditioning regimens have been selected for the comparison: intravenous Bu at the total dose 12.8 mg/kg (4 days) + Flu (Bu4Flu, N=60) or TBI at the total dose of 12 Gy given in three fractions + Flu (TBI12Flu, N=40).Results: 100 patients (Bu4Flu, n=60; TBI4Flu, n=40) were included in the analysis. Median age was 42 (19-62) years in Bu4Flu group and 36 (19-64) for TBI12Flu group (p=0.01). Proportion of patients given transplant from URD was 72% and 70%, respectively (p=NS). The rates of patients treated with HSCT CR1, CR>1 and active disease were 75%, 25%, 0% in the Bu4Flu group while 82.5%, 10% and 7% in the TBI12Flu group (p=NS).All patients engrafted except for one patient in the TBI12Flu group who died of infection before engraftment. Time to neutrophil recovery was significantly faster after TBI12Flu (median 15 days, range 11-24) compared to Bu4Flu (18, 12-36 days) (p=0.000007). With the median follow up of 18 months, the cumulative incidence of relapse at 2 years was 11% (+/-6) and 30% (+/-7), respectively (p=0.14) while NRM was 19% (+/-8) and 10 (+/-5%), respectively (p=0.34). The probability of OS was 76% (+/-8) after TBI12Flu and 71% (+/-7%) after Bu4Flu (p=0.69). The LFS rates were 70% (+/-8%) and 60% (+/-7%), respectively (p=0.53). No signficant differences regarding survival could be detected in analysis restricted to patients transplanted in CR.Conclusion: Both Bu4Flu or TBI12Flu as conditioning regimens pre-alloHSCT for patients with AML are highly effective, which together with acceptable tolerance leads to survival rates of more than 70% at two years. TBI12Flu is associated with faster engraftment and a tendency to reduced risk of relapse. Prospective studies comparing both regiemens are needed. DisclosuresNo relevant conflicts of interest to declare.

Supernumerary Incisors in CB6F1 Mice Conditioned with Chemotherapy and Total Body Irradiation before Bone Marrow Transplantation.

Multiple adult female CB6F1 mice presented with supernumerary incisors after preconditioning with chemotherapy and total body irradiation for bone marrow transplantation (BMT). Mice received nonmyeloablative total body irradiation (3 Gy) and either cyclophosphamide or bendamustine, followed by BMT and posttransplantation cyclophosphamide or bendamustine. Here we describe the clinical presentation, μCT findings, and histopathologic evaluation of the affected mice. These analyses confirmed the gross diagnosis and revealed details of the abnormal tooth morphology. We surmise that the combination of total body irradiation and chemotherapy resulted in the abnormal formation of supernumerary incisors. Supernumerary teeth should be considered as a potential confounding factor in tracking weight loss after BMT. These conditions can be managed to allow animals to reach their intended scientific endpoint.

Методика стыковки полей при тотальном облучении тела с использованием технологии томотерапии

Purpose: Combination of total body irradiation (TBI) with chemotherapy is widely used technique for conditioning before hematopoietic stem cell transplantation for patient with hematological malignancies worldwide. Total body irradiation for patients with high height has to be divided into two parts: irradiation of upper part of the patient’s body (including head, body and part of legs) and irradiation of lower part of the patient’s body (including leg). There is an area in which the fields overlap each other – the junction area. The aim of this work is the development and verification of simple junction technique that would provide the dose distribution in the junction area from 90 to 125 % of prescribed dose.&#x0D; Material and methods: Total body irradiation was performed on the Tomotherapy machine using helical geometry of the beam delivery. Distribution of the dose in junction area was investigated. Simple solution was proposed: during the optimization of the radiotherapy plan certain margin should be maintained between upper and lower targets while dose distribution in junction area satisfies the uniformity requirements for the given irradiation geometry. The dimension of the margin was determined experimentally using a CheesePhantom and radiochromic EBT-2 films. The uniformity of dose distribution in the junction area was monitored by in vivo measurements using radiochromic EBT-2 films located on the skin surface of patients.&#x0D; Results: The dimension of the margin at which the dose in the junction area is within the range of 90 to 125 % of the prescribed dose was determined experimentally and amounted to 5.25 cm. The values of the measured dose were in the range from 97 to 105 %. In total 18 in vivo measurements of the junction area were performed. According to the results of in vivo dosimetry, the values of the doses measured in the junction area were in the range from 93 ± 3 % to 108 ± 4 %.&#x0D; Conclusion:The developed planning method with the selected plan geometry ensures satisfactory heterogeneity of the dose distribution in the area of field junction between the upper and lower irradiation regions, despite of the existing uncertainty of patient positioning. Results were confirmed by in vivo measurements. The obtained data can be used for total body irradiation of the patients using Helical Tomotherapy.

Successful Early Outcome with Low-Dose (400 cGY) Total Body Irradiation in Combination with Busulfan and Fludarabine Myeloablative Conditioning Followed By Matched Unrelated Donor Allogeneic Peripheral Blood Stem Cell Transplantation in a Patient with Non-Remission Acute Myelogeneous Leukemia with Diffuse Extramedullary Disease in Multiple Sites

Outcome after allogeneic stem cell transplantation (allo-SCT) is poor with 10-20% probability of long term survival in patients with acute myelogeneous leukemia (AML) not in remission at the time of transplant. The main cause of transplant failure in this high risk population is disease post-transplant relapse. We treated a 32 year-old male with undifferentiated AML (M0) who initially presented with leukocytosis, circulating blasts and a large anterior mediastinal mass abutting adjacent structures. A core biopsy of the mass revealed myeloid sarcoma. Patient developed respiratory distress requiring endotracheal intubation and mechanical ventilation. Cytogenetics revealed Hyperdiploid, 55, XY,+4,+6,+8,+9,+10,+11,+14,+19,+mar[12]/46,XY[14]. FLT3 ITD was positive. He did not respond to initial induction chemotherapy with 7+3 (daunorubicin 60 mg/m2/d and Cytarabine 100 mg/m2/d). He achieved morphologic and cytogenetic complete remission after re-induction with high dose cytarabine and mitoxantrone. He also received scheduled prophylactic triple intrathecal chemotherapies throughout his treatment course and started high dose cytarabine consolidation (HIDAC). His treatment courses were complicated by numerous medical problems, requiring a second prolonged hospitalization following third consolidation. He was intubated again due to diffuse alveolar hemorrhage. The patient was eventually discharged with tracheostomy collar and supplement oxygen, which was discontinued later on. A follow-up CT of chest showed increase in size of mediastinal mass but continuous CR in BM exam. While unrelated donor allogeneic SCT is in process, he received one course of decitabine. At the time of pre-transplant work-up, he relapsed of her AML first at his left conjunctivae and shortly after on his skin, presented with diffuse chloroma lesions on his trunk. He was treated with external radiation to his left eye with additional IT chemo (negative cytology). He underwent 10/10 HLA match unrelated donor allogeneic stem cell transplantation following PK-directed IV Busulfan with targeted AUC of 20,000 and Fludarabine 160 mg/m2 plus total body irradiation 200 cGY/d x 2 days. Skin lesions were active but bone marrow was in remission at the time of transplant. GVHD prophylaxis was tacrolimus and low dose methotrexate 5 mg/m2/d on days+1, +3, and +6 only. No ATG was given. His post-transplant course was relatively unremarkable. No major complications requiring re-admission to hospital occurred. His trach collar was kept thoughout his transplant and post-transplant courses due to tracheal stenosis. He achieved complete morphologic and cytogenetic remission with resolution all of his extramedullary leukemia including his mediastinal mass on day+100 evaluation. Currently he has been receving monthly 5-Azacitidine maintenance and clinically well on day+122. This case illustrates a successful early outcome after peripheral blood allogeneic stem cell transplantation using the combination of chemo-low dose radiation in a patient with non-remission AML with diffuse extra medullary disease. Optimum combination of radiation and chemotherapy in conditioning regimens may improve transplant outcomes in patients with non-remission AML and warrants prospective Phase I-II clinical trials. DisclosuresNo relevant conflicts of interest to declare.

THE POTENTIATION OF THE RADIOPROTECTIVE EFFICACY OF TWO MEDICAL COUNTERMEASURES, GAMMA-TOCOTRIENOL AND AMIFOSTINE, BY A COMBINATION PROPHYLACTIC MODALITY.

This study was designed to evaluate the possible potentiation of survival protection afforded by relatively low-dose amifostine prophylaxis against total body irradiation in combination with a protective, less toxic agent, gamma-tocotrienol (GT3). Mice were administered amifostine and/or GT3, then exposed to 9.2 Gy 60Co γ-irradiation and monitored for survival for 30 days. To investigate cytokine stimulation, mice were administered amifostine or GT3; serum samples were collected and analyzed for cytokines. Survival studies show single treatments of GT3 or amifostine significantly improved survival, compared to the vehicle, and combination treatments resulted in significantly higher survival compared to single treatments. In vivo studies with GT3 confirmed prior work indicating GT3 induces granulocyte colony-stimulating factor (G-CSF). This approach, the prophylactic combination of amifostine and GT3, which act through different mechanisms, shows promise and should be investigated further as a potential countermeasure for acute radiation syndrome.

The first Russian experience of TomoTherapy for total body irradiation in children

Background. Combination of total body irradiation (TBI) with chemotherapy is widely used technique for conditioning before hematopoietic stem cell transplantation for patient with hematological malignancies worldwide. Best results of patient’s survival were showed in comparison with conditioning regimen included only chemotherapy. Aim – development of TBI technique at children with the help of TomoTherapy equipment and including it to the conditioning protocol before allogenic bone marrow transplantation. Materials and methods. During the period between July 2014 and February 2016 radiation therapy was made for 38 patients. Treatment was performed daily, 2 times per day with single basic dose on extended target (PTV) 2 Gr to total focal dose 12 Gr. Taking into account potential sensitivity of healthy organs and based on literature data, the following risk organs were chosen: lungs, kidneys and anterior eye chamber. Results. All patients successfully passed the planned program of treatment. Follow-up period was from 0 to 21 months (average – 7.2 months). No one of the patients did not showed any toxic episodes from the critical organs (lungs, kidneys, eye lens). Conclusions. TBI on TomoTherapy equipment allows to provide maximal control on irradiation dose distribution in PTV with the decreasing of radiation for critical organs. This allows achieving the decreasing of possibility of serious complications of radiation therapy and high effectiveness of treatment.

Thymic Activity and T Cell Repertoire Recovery after Autologous Hematopoietic Stem Cell Transplantation Preceded by Myeloablative Radiotherapy or Chemotherapy

It was previously postulated that pretransplant myeloablative treatment may impair thymopoiesis, contributing in this way to delayed reconstitution of T cells after hematopoietic stem cell transplantation (HSCT). On the other hand, de novo generation of T cells after HSCT requires a competent thymus. Various myeloablative conditioning regimens (total body irradiation [TBI] or high-dose chemotherapy) routinely used in clinical practice may have potentially different impacts on the thymus. However, no comparative study on thymic output and T cell repertoire in autologous (auto)HSCT model has been presented so far. Here we evaluated thymic output and TCR diversity in 45 lymphoma patients submitted to autoHSCT differing in respect to conditioning regimen: high-dose chemotherapy as monotherapy (BEAM, n = 22) or combination of total body irradiation with cyclophosphamide chemotherapy: Cy/TBI (n = 23). Thymic output was assessed before and on days +100, +180, and +365 after autoHSCT by flow cytometric counts of recent thymic emigrant (RTE) cells (CD31+ CD62L+ CD45RA+ CD4+) and quantification of signal joint TCR receptor excision circles (sjTRECs) by quantitative PCR. T cell repertoire diversity was analyzed on day +365 after autoHSCT by spectra-typing of the CDR3 region in the TCRVβ chain. The BEAM group, in contrast to the Cy/TBI group, manifested significantly higher proportions of RTE cells and sjTREC copy numbers on days +100 and +180. Analysis of TCRVβ spectra-types on day +365 revealed more restricted (monoclonal or oligoclonal) T cell repertoires in the Cy/TBI versus BEAM group (48.8% versus 18.2%, P = .0002). In conclusion, the conditioning scheme based on BEAM chemotherapy may be performed with lower risk of thymic destruction and T cell repertoire distortion than Cy/TBI scheme. This finding may help to potentially improve conditioning schemes to efficiently perform myeloablation and maintain active thymopoiesis.

Allogeneic Hematopoietic Cell Transplantation For Patients With Primary and Secondary Myelofibrosis: Report Of a Single Center Experience

Introduction Myelofibrosis (MF) is a heterogenous myeloproliferative disorder arising at the level of pluripotent hematopoietic stem cells. It is characterized by reactive marrow fibrosis resulting in extramedullary hematopoeisis, cytopenias, hepatosplenomegaly and constitutional symptoms. The only curative treatment for MF patients is allogeneic hematopoietic cell transplantation (HCT). However, advanced age, comorbidities and disease-related complications are challenging factors for allogeneic HCT. Reduced intensity conditioning (RIC) regimens have lead to an increased frequency of allogeneic HCT for MF patients in recent years. We here report our own experience with allogeneic HCT in MF. Methods By searching our database of allogeneic HCT we identified a total of 55 patients with primary or secondary myelofibrosis that underwent allogeneic HCT from 1997 to 2012. Retrospective analysis of data and review of patient charts was performed. Results Among the 55 MF patients were 32 males and 23 females with a median age of 54 years (range 28-75). The median interval from diagnosis to HCT was 123 months (range 2-269). Conditioning regimens were either myeloablative (MAC, 18/55 patients (33%)) or RIC (37/55 patients (67%)). Median age was 58 years (range 45-75) for RIC und 47 years (range 28-60) for MAC. As graft source either peripheral blood stem cells (n= 46) or bone marrow (n= 9) was used from either matched related (MRD, n=17, 31%), matched unrelated (MUD, n=21, 38%) or mismatched unrelated donors (MMUD, n=17, 31%). The MAC regimen consisted of 12 Gy total body irradiation in combination with high-dose cyclophosphamide (TBI/Cy, 78%) or high-dose busulfan and cyclophosphamide (Bu/Cy, 22%). Fludarabine and busulfan were the most frequently applied drugs for RIC (Flu/Bu, n=31, 84%), in a few cases fludarabine in combination with TBI (n=1, 3%) or treosulfan-containing regimens (n=3, 8%) were used. Two patients with accelerated disease were treated with the FLAMSA-protocol, followed by busulfan and cyclophosphamide containing RIC. As graft versus host disease (GVHD) prophylaxis, a combination of calcineurine inhibitors and methotrexate or mycophenolate mofetil was used, in 80% (n=44) antithymocyte globuline was additionally applied. Kaplan Meier estimated overall survival at 4 years was 62% for all patients and 62% after RIC compared to 58% with MAC (p= 0.42) with a median follow-up of patients alive of 49 months (range 9-151). Cumulative incidence of non relapse mortalitiy (NRM) overall and for MAC and RIC was 31%. The overall survival of patients with MRD, MUD and MMUD was 60%, 61% and 61%, respectively. NRM of patients with matched and unmatched donors was not significantly different (MRD 31% versus MUD 35% versus MMUD 33%). Engraftment of neutrophils (ANC&gt;500/µL) was achieved at a median of 16 (range 9-31) days and 23 (range 13-60) days for patients in the MAC and the RIC-group, respectively (p= 0.0051). Platelet recovery (PLT&gt;20.000/µL) occurred at a median of 24 (range 11-51) days after MAC and 21 (range 8-41) days after RIC (p= 0.2866). Despite the significantly delayed engraftment, the risk for severe or lethal infection was lower in the RIC- than in the MAC-group (n=3 versus n=1). Graft rejection occurred only in 3 patients after RIC. Acute GVHD occurred in 31% (n=17) of the patients. As expected, patients with MAC, compared to RIC, had a higher risk of acute GVHD (71% (n=12) versus 29% (n=5), p&lt; 0.0001). Chronic GVHD occured in 59% of the patients, with 44% extensive and 56% limited cases. Chronic GvHD was more frequent after RIC compared to MAC (59% versus 41%, p= 0.1462). Patients with an extensive GVHD only survived in 18%, whereas patients with a mild or limited GvHD survived in 39% (p= 0.2059). Overall the occurence of GVHD was associated with a poorer outcome. Conclusion Our retrospective single center study confirms existing data that allogeneic HCT following RIC may have a similar outcome compared to MAC although used in an older and more comorbid patient population. Allogeneic HCT even with MMUD thus is a potentially curative treatment option in up to 60% of patients with primary or secondary MF. Disclosures: No relevant conflicts of interest to declare.

Total body irradiation enhances the anti-tumor efficacy of adoptively transferred CD8+ T cells stimulated ex vivo with IL-12 (162.41)

Abstract Stimulation of T cells with IL-12 improves their cytolytic capabilities and ability to persist in vivo. Despite these enhanced functional characteristics, we have found that these cells can only eliminate established tumors in mice preconditioned with cyclophosphamide (CTX). While this result demonstrates the importance of lymphodepletion in adoptive cell transfer (ACT) regimens, it is unclear if other forms of lymphodepletion would also enhance the efficacy of IL-12 primed cells. Since the most successful lymphodepleting regimen in metastatic melanoma clinical trials uses total body irradiation (TBI), we sought to determine if TBI preconditioning combined with ACT of IL-12 stimulated pmel-1 CD8+ T cells might be similarly synergistic. When we adoptively transferred pmel-1 CD8+ T cells primed with antigen and IL-12 (pmelIL-12) into mice preconditioned with TBI, we saw significantly elevated numbers of donor T cells compared with mice adoptively transferred with pmel-1 CD8+ T cells primed with antigen alone (pmelsham). Importantly, the increase in donor T cell numbers seen with the combination of TBI + pmelIL-12 translated to significant delays in melanoma outgrowth. Strikingly, the addition of pmelsham to TBI preconditioning resulted in no improvement in anti-tumor immunity compared to TBI alone. Thus both CTX and TBI host preconditioning greatly enhance the anti-tumor efficacy of transferred T-cells stimulated with IL-12.

Myeloablative Conditioning with Pharmacokinetic-Targeted Intravenous Busulfan and Cyclophosphamide in Unrelated Cord Blood Transplantation for Myeloid Malignancies in Children

Abstract 1965Unrelated cord blood transplantation (UCBT) has been an increasingly used stem cell source in hematopoietic stem cell transplantation for myeloid malignancies in children when a related HLA-identical donor is unavailable. Advantages of UCBT include a less stringent HLA compatibility and prompt availability.Myeloablative regimens for UCBT use a combination of total body irradiation or Busulfan (Bu) with Cyclophosphamide (Cy) or other chemotherapy agent. Intravenous Bu has a more predictable bioavailability comparing with oral Bu. Nevertheless, there is still an important variation in Bu pharmacokinetics (PK) between patients. Dose modification of Bu based on its first-dose PK might decrease the risk of toxicity and graft rejection and increase its antitumoral effect.In order to analyse the role of a myeloablative conditioning regimen of PK-adapted Bu for myeloid malignancies we analyzed 30 consecutive first UCBT performed in children between dec/2000 and aug/2010. Median age at transplant was 6.3(0.6-17.3) years, 18 (60%) were male and median weight was 26.2 (6.9-81.1) kg. There were 18 acute myeloid leukemia (AML) and 12 myelodysplastic syndromes (MDS). Seven, nine, and two patients with AML were transplanted in first remission (CR1), second remission (CR2), or in advanced phase of disease (>CR2 or in relapse), respectively. Twenty-eight patients received a single UCBT. Seven, thirteen, and ten patients received a 6/6, 5/6 and 3–4/6 HLA-matched graft. Median infused nucleated cells (NC) and CD34+ cells were 5.28 × 107/kg and 2.07 × 105/kg of recipient body weight, respectively. Cyclosporin A and steroids were used as graft versus host disease (GvHD) prophylaxis. All patients received anti tymoglobuline.Conditioning regimen consisted of PK-adapted Bu (targeted steady-state concentration - Css - between 600–900 ng/ml) and Cy 200 mg/kg (n=27), Melphalan 135 mg/m2 (n=2) or Cy 120 mg/kg and etoposide 30 mg/kg (n=1). PK data were available for all but one patient. For five patients the initial prescribed dose of Bu was not changed, for two patients initial prescribed dose of Bu was decreased and for 22 patients the initial prescribed dose of Bu was increased (median increase of 24.8% - range: 5.3–56,3 %).Median follow-up was 53 months.Cumulative incidence (CI) of neutrophil (>0.5×109/L) at D+60 and platelet recovery (>50×109/L) at D+150 was 83% and 83%, respectively. Median time to neutrophil and platelet recovery was 20 days and 69 days, respectively. There was a single case of graft failure. CI of acute GVHD grade II-IV at D+180 was 14% (with one case of grade III aGvHD). There were two cases of VOD (one mild and one moderate). Two-years CI of transplant-related mortality (TRM) was 17% (three patients died due to infections and one due to graft failure). CI of relapse at 2 years was 30% (with all relapses occurring within two years of UCBT). Event-free survival (EFS) at 5 years was 53%. EFS for patients with MDS (67%) and AML (45%) were not significantly different (P=0.45). Overall survival (OS) at 5 years was 61%. There was a tendency to a better OS for patients with MDS vs AML (83% vs 49% - P=0.19). For AML, disease status did not influence survival.In conclusion, UCBT for myeloid malignancies is a viable option when a HLA-identical sibling donor is unavailable. PK study for ivBu is important as most patients needed Bu dose adjustment. PK-adapted BU seems to reduce acute toxicity and graft failure. However TRM due to infection and relapse remains a problem. New conditioning regimens associating fludarabine with PK-adapted Bu alongside with modification in GvHD prophylaxis to improve immunological recovery might contribute to further decrease TRM and relapse and improve UCBT results, especially for AML. Disclosures:No relevant conflicts of interest to declare.